Police say an argument broke out while players were in a handshake line after the game between Simeon Career Academy and Morgan Park High School. The two students involved in the shoving incident after the game have been suspended for their team's next regular game, according to CPS.

The dispute spilled into the parking lot near 95th Street and King Drive and someone pulled out a gun and shot Lawson around 9:30 p.m., officials said.

Lawson died from multiple gunshot wounds in a homicide, the Cook County medical examiner’s office determined this afternoon. Lawson was shot twice in the back while running away, said Kurtistein Bailey, his 41-year-old aunt. Amid the chaos, someone knelt down and told Lawson to get up but he couldn't move, his aunt said.

"This was at the school where his mom thought he was safe," Bailey said. "His mother thought he was safe there. That's why she let him go."

Lawson had sent a text message to this mother earlier in the day, asking if he could go to the game. "Mom, can I go to the basketball game? It's only $10," Lawson had asked, according to VanHughs.

"I texted him back 'K,' and he said 'light' because he always said 'light' instead of 'right,'" said Wright, 52.

Before she dropped him off at the game, Wright gave him $17 -- $10 for the game and $7 to spend -- and told him to "be careful."

His mother waited for him to call back or text her, she said.

A fight broke out at the end of the game, and video shows security getting players off the court. It was unclear what the fight was about. Nothing outside ordinary bumps and physical contact appeared to have happened during the game between the two schools, which are located on Vincennes Avenue about 30 blocks apart.

Around 8:30 p.m., Wright wanted to check on her son, but her 53-year-old fiance, Gregory Young, assured her Lawson was "all right." About an hour later, Wright learned from a relative that Lawson had been "hit twice in the back" and died, she said.

University police issued a message to its officers, asking them to watch for a Jeep. It was pulled over east of the school and two people were taken into custody, officials said. Police said they found a gun inside the Jeep.

The Jeep's owner told the Tribune this afternoon that she was not aware of any gun in the car. "I was not there," the owner said. "I don't know what happened."

Wright said she and Young were planning on telling Lawson today that they were getting married next week. Now, the two are tying the knot Feb. 26, Lawson's birthday.

CPS spokeswoman Marielle Sainvilus said the district worked with the university and Chicago police to provide security at the game.

Sainvilus said there was a significant security presence both inside and outside the gym, and there had been screening to prevent anyone from carrying guns into the game. All fans were also searched.

The university released a statement Thursday morning saying it was "deeply saddened by the tragic shooting death."

“(Chicago Public Schools) periodically uses the university’s athletic facility to provide a neutral setting for student sporting events. This is the first such incident to occur on the campus of Chicago State University where CPS students have played many times over the last three years," the statement said.

"Additional security is provided by the university and all external partners during high school sporting events. Arrests have been made and university officials are awaiting the outcome of a full investigation to learn details about the shooting incident.”

Relatives said Lawson was an honor student at Morgan Park and hoped to land a ComEd apprenticeship after graduation. They remembered him as "high-spirited" and "loved by all," a popular student with friends on the basketball team.

Bailey said Lawson loved animals, and took care of snakes, an iguana and turtles over the years. His grandmother said he loved animals so much he gave up his bedroom for his 2-year-old dog, Midnight, and slept on a futon in another room.

VanHughs said she helped raise Lawson while his mother traveled for her job. Family members described the two as having a strong relationship.

"He was definitely a momma's boy," Bailey said. "They were very close and he was her only child."

CPS chief Barbara Byrd-Bennett ordered extra security personnel for the two high schools today. Crisis teams, including counselors, also have been deployed at Morgan Park.

CPS would not release any information about Lawson's education history or attendance at Chicago Public Schools.